Power efficiency of processor-based devices is of growing importance, and in particular, for devices powered by a battery, power efficiency is a key issue that has to be considered. Accordingly, various research into increasing the power efficiency of devices has been conducted recently.
In general, a register that stores pieces of information necessary for performing an operation of a processor includes a plurality of input/output ports so as to perform at least two operations simultaneously. Among the plurality of input/output ports, only some of them that are necessary for the processor to perform the operation may be used. In the related art, there is a problem in that, even when a read port from among the plurality of input/output ports is not used in the operation, every read port is assigned an arbitrary address value all the time and performs a meaningless operation.